Battery Tender Again
Thread Starter
Racer
Joined: Dec 2007
Posts: 262
Likes: 12
From: Montgomery Alabama
Battery Tender Again
I do not know if this is the way tenders work but here is the scenario. I keep my 1993 base coupe on the battery tender when not using. The tender charges (?) and then goes into the maintenance mode. But when I start engine, the voltmeter reads 15 volts and gradually drops to 14.1. Is this normal? Thanks for your help as usual. I really appreciate it.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
When you start it, you draw a lot of power from the batt. The alternator works hard initially to recharge the battery, so volts might show that for a minute. If you had an AMP gauge on the car (like older cars did), you'd see a similar spike in amps on start up, diminishing to operating load over a period of about 10-15 seconds.
Safety Car
Joined: Aug 2000
Posts: 4,148
Likes: 642
From: Bandera Texas
I do not know if this is the way tenders work but here is the scenario. I keep my 1993 base coupe on the battery tender when not using. The tender charges (?) and then goes into the maintenance mode. But when I start engine, the voltmeter reads 15 volts and gradually drops to 14.1. Is this normal? Thanks for your help as usual. I really appreciate it.
Pro
Joined: Aug 2019
Posts: 596
Likes: 146
From: Minford, Ohio
The alternator has a regulator built into it. The regulator regulates the voltage and the current output of the alternator. As long and the battery stays charged while driving it on a regular basis then the alternator is working. On most 12v systems the alternator will put out between 13 and 14.5 volts at normal operating temperature. If you don't drive it for several weeks with the tender connected to the battery and the car will start after that amount of time, your tender is working.
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